Reference node placement and selection algorithm based on trilateration for indoor sensor networks

The key problem of location service in indoor sensor networks is to quickly and precisely acquire the position information of mobile nodes. Due to resource limitation of the sensor nodes, some of the traditional positioning, algorithms, such as two-phase positioning (TPP) algorithm, are too complicated to be implemented and they cannot provide the real-time localization of the mobile node. We analyze the localization error, which is produced when one tries to estimate the mobile node using trilateration method in the localization process. We draw the conclusion that the localization error is the least when three reference nodes form all equilateral triangle. Therefore, we improve the TPP algorithm and propose reference node selection algorithm based on trilateration (RNST), which call provide real-time localization service for the mobile nodes. Our proposed algorithm is verified by the simulation experiment. Based on the analysis of the acquired data and comparison with that of the TPP algorithm, we conclude that our algorithm call meet real-time localization requirement of the mobile nodes ill an indoor environment, and make the localization error less than that of the traditional algorithm: therefore our proposed algorithm call effectively solve the real-time localization problem of the mobile nodes in indoor sensor networks. Copyright (C) 2008 John Wiley & Sons, Ltd.